【摘要】 采用超高真空落管无容器处理技术研究了Fe-19.1%Si-7.8%Ti三元共晶合金的快速凝固。理论计算表明,在自由落体条件下Fe-19.1%Si-7.8%Ti三元共晶合金获得的过冷度范围为:37~259K;冷却速率范围为:4.81×103~2.48×105K/s。由XRD和EDS点分析结果得出,在较小过冷度下,合金的凝固组织由(Fe3Si+Fe5Si3)二相共晶和(Fe2Si+τ3)二相层片共晶构成,生成(Fe2Si+τ3)二相层片共晶的原因可能是发生了Fe3Si+Fe5Si3→Fe2Si+τ3固态相变;在大过冷度下,(Fe2Si+τ3)二相层片共晶消失,固态相变被抑制。更多还原

【Abstract】 The rapidly solidification of Fe-19.1%Si-7.8%Ti ternary eutectic alloy was studied adopting ultrahigh vacuum drop tube no container processing technology. Theoretical analysis indicate that, with the decrease of droplet diameter, the undercooling and cooling rate increase exponentially, the maximum undercooling is 259 K in this study, the cooling rate changes from 4.81×103K/s to 2.48×105K/s. The EDS and XRD measurements reveal that the solidification microstructure are composed of(Fe3Si+Fe5Si3) eutectic and the lamellar(Fe2Si+τ3) eutectic under small undercooling. It cannot be ruled out that solid state reaction Fe3Si+Fe5Si3→Fe2Si+τ3occur. Whereas the solid state reaction is suppressed at large undercooling,the lamellar(Fe2Si+τ3) eutectic phases vanish.更多还原